The present invention relates to an adjustable assembly. More particularly, the present invention relates to an adjustable assembly especially suited for use in a body fluid sampling device.
In the description of the background of the present invention that follows reference is made to certain structures and methods, however, such references should not be construed as an admission that these structures and methods qualify as prior art under the applicable statutory provisions. Applicants reserve the right to demonstrate that any of the referenced subject matter does not constitute prior art with regard to the present invention.
Many medical procedures in use today require a relatively small sample of bodily fluid. The term bodily fluid is intended primarily to encompass blood, interstitial fluid, or a mixture of the two, however, the term could also include urine, saliva, etc. Such samples are often obtained by lancing or piercing the skin at a selected location, such as the finger, to enable the collection of 1 or 2 drops of blood.
With the advent of home use tests such as self monitoring of blood glucose, there is a requirement for a simple, reliable procedure which can be performed in any setting by a person needing to test, and which minimizes discomfort to the person being sampled and tested.
Lancets in conventional use generally have a rigid body and a sterile needle which protrudes from one end. The lancet may be used to pierce the skin, thereby enabling the collection of a sample from the opening created. Blood is commonly taken from the fingertips, where the supply is generally excellent. The nerve density in this region causes significant pain in many patients. Repeated lancing of the fingertips results in callous formation. This leads to increased difficulty in drawing blood and increased pain.
Sampling of alternate site, such as earlobes and limbs, is sometimes practiced to access sites which are less sensitive. However, obtaining an adequate sample, and transferring the sample to a test strip or reading device, from such non-fingertip locations often proves to be difficult.
To reduce the anxiety of piercing the skin and the associated pain, many spring loaded devices have been developed. U.S. Pat. No. 4,503,856 to Cornell et al. and U.S. Pat. No. 4,517,978 to Levin et al. are representative of the devices which were developed in the 1980""s for use with home diagnostic test products, the disclosures of which are incorporated herein by reference in their entirety. Even with the large amount of activity and development in this area, many conventional devices have undesirable aspects.
U.S. Pat. Nos. 5,879,311; 5,857,983; 6,048,352; 5,951,492; 5,951,493; 5,964,718; and 6,086,545 represent important advance(s) in this area. The disclosures of these patents are incorporated herein by reference, in their entirety. Through the constructions and methods set forth in these patents, adequate samples of bodily fluid are reliably obtained, even from non-fingertip locations, in a minimally invasive and substantially pain-free manner.
At least some of the above-mentioned U.S. Patents involve applying a skin-lancing medium against a skin surface to form an incision therein, removing the skin-lancing medium from the incision, and thereafter applying a force to depress the skin in a manner forming a ring of depressed body tissue in surrounding relationship to the incision, causing the incision to bulge and the sides of the incision to open, whereby bodily fluid is forced out through the opening of the incision. This enables an adequate and adjustable sample size to be obtained, even from areas of the body in which the blood supply is less plentiful, with a minimally invasive lancing procedure.
In this regard, the sampling device can include having a housing with a lower end. At the lower end of the housing a stimulator mechanism is provided which is relatively movable with respect to the housing and which has an end face adapted to engage the skin surface and bulge open the lanced opening in response to being pressed one or more times against the skin surface. This construction facilitates the extraction of the bodily fluid, thereby enabling an adequate sample to be obtained from a relatively small lanced incision in the skin surface and reducing the pain associated with such techniques.
While the above-mentioned construction is clearly advantageous, it would also be beneficial to provide such a construction and technique with a simple, user-friendly and reliable way to adjust the depth of penetration of the lancet into the surface of the skin.
The are numerous known devices which per se provide an adjustable depth of penetration of a lancet into the surface of the skin.
U.S. Pat. No. 4,895,147 to Bodicky et al. discloses a lancet injector which includes an elongate tubular housing, and a penetration depth selector disposed thereon. The rotatable depth selector includes a number of variable depth contact edges. These contact edges present a jagged surface which is exposed on the outside of the housing. This construction is undesirable, since such exposed jagged edges could pose a safety concern, and do not present an aesthetically pleasing form. The aesthetics of such devices are of particular importance since the users are already apprehensive due to the traditionally painful nature of the testing procedure. Thus, a relatively more aesthetically pleasing design will reduce such apprehension and encourage more frequent use which is important in situations such as the self-monitoring of blood glucose content. Moreover, Bodicky et al. does not disclose a device including a stimulator mechanism which is relatively movable with respect to the housing. Thus, the device of Bodicky et al. is not as effective in extracting an adequate sample of bodily fluids, especially from non-fingertip locations.
U.S. Pat. No. 6,022,366 to Schraga discloses a lancet device including an adjustable penetration depth mechanism. In one embodiment, Schraga discloses a device wherein the penetration depth is adjusted by adjusting the length of the needle holding member. According to this embodiment, a proximal segment is rotated relative to a cental segment, thereby increasing or decreasing the overall length of the needle holding member. During rotation, a protruding element snaps into and out of grooves provided on the inner diameter of the proximal segment. However, such a construction provides for a relatively limited number of adjustments because only a limited number of grooves can be disposed upon the inner diameter of the proximal segment, due to the relatively small size typical in such devices. Moreover, the device described by Schraga requires that the user remove the cap member in order to adjust the penetration depth, then the cap member must be replaced by the user after the adjustment has been made. This construction is obviously inconvenient to the user, adds an extra degree of difficulty to the operation of the device, and could pose a safety hazard due to the potential exposure of the user to the sharp lancet needle during the adjustment process. Moreover, the device of Schraga does not include a stimulator mechanism, or a stimulator mechanism which is relatively movable with respect to the housing. Thus, the device of Schraga lacks the desirable degree of effectiveness in extracting an adequate sample from non-fingertip locations, particularly with a minimally invasive lancing procedure.
U.S. Pat. No. 5,613,978 to Harding discloses an adjustable tip for a blood lancet device for causing different depths of skin puncture. The device of Harding includes an inner sleeve and a partially enclosed distal end which forms a stop for the shoulder of the lancet. Rotation of an outer sleeve causes longitudinal motion between the distal ends of the inner sleeve and outer sleeve, thereby creating an adjustable double bottom which creates various puncture depths. However, the device of Harding is for fingertip sampling. Nowhere does Harding disclose, or even suggest, that a device having the construction described therein is suitable for non-fingertip sampling. Moreover, the device of Harding lacks a stimulator member, much less a stimulator member which is relatively movable with respect to the housing. Thus, the device of Harding is not suitable for minimally invasive sampling, particularly at non-fingertip locations.
U.S. Pat. No. 6,045,567 to Taylor et al. discloses a lancing device having a spring-loaded lancet holder slidably mounted within a housing. The device is further provided with a knob on the back of the device which includes forwardly extending fingers that act to stop the lancet holder at an adjustable predetermined point after the device has been fired. Thus, the fingers act to control the penetration depth of the needle. However, the device of Taylor et al. is specifically constructed for fingertip sampling. Nowhere does Taylor et al. mention, or even suggest that the device constructed as described therein is suitable for non-fingertip sampling. Moreover, the device of Taylor et al. lacks a stimulator member, or a stimulator member which is relatively movable with respect to the housing. Thus, the device of Taylor et al. is not suitably constructed for non-fingertip minimally invasive sampling.
U.S. Pat. No. 5,730,753 to Morita describes an assembly which comprises a cap element for mounting onto an injector. The cap has a stop which is constructed such that an end of the lancet from which the lancing member protrudes abuts against the stop during operation of the device. The device further includes an adjusting element which engages the cap, as well as a cover element between these elements. The distance between the stop and an opening along a direction of the lancet movement is changed by rotating the adjusting element around an axis of rotation of the lancet ejector. However, the device described by Morita is heavily dependent upon the elasticity of the material which makes up the various components. Thus, this construction is more readily prone to failure, due to failure of the material from which it is constructed. This is particularly important since it is beneficial to construct such devices of relatively inexpensive materials in order to reduce cost to the consumer. The device of Morita is specifically constructed for application in finger stick devices. Thus, Morita give no indication that the device described therein would be suitable for minimally invasive sampling and non-fingertip locations. Moreover, the device of Morita does not include a stimulator member, or a stimulator member which is relatively movable with respect to the housing thereof.
Thus, it would be desirable to provide an improved assembly which enables the penetration depth of a lancing member to be adjusted in a simple yet effective and reliable manner, particularly in devices which are constructed for the sampling of bodily fluids in non-fingertip locations, with a minimally invasive lancing procedure.
It is an object of the present invention to provide an adjustable assembly which overcomes the problems associated with the prior art.
According to one aspect, the present invention provides an adjustable arrangement comprising a carrier; a guide tube, the guide tube receiving the carrier in a longitudinally slidable manner, the guide tube comprises a stop member limiting longitudinal movement of the carrier; an inner ring, the inner ring adjustably attached to the guide tube, the inner ring comprising a bottom surface adapted to contact a surface of the skin and to depress a ring of body tissue; an outer ring, the outer ring receiving the inner ring in a longitudinally slidable and relatively nonrotatable manner; and a retainer ring, the retainer ring receiving the guide tube in a longitudinally fixed and relatively nonrotatable manner, the retainer ring receiving the outer ring in a longitudinally slidable and relatively rotatable manner.
According to a further aspect, the present invention provides an arrangement of interfitting components for adjusting the penetration depth of a lancet and for stimulating an area surrounding an incision formed by penetration of a surface of the skin by the lancet, thereby facilitating the extraction of a sample of bodily fluid with a minimally invasive incision, the arrangement comprising a bottom end adapted to be applied to the surface of the skin, and a top end opposite the bottom end; a longitudinally moveable lancing member having a sharp end; a stop member setting a longitudinal travel distance of the lancing member; a bottom surface adapted to be applied to the surface of the skin, and an opening in the bottom surface through which the lancing member projects; a penetration depth defined by the distance between the end of the lancing device and the bottom surface; adjusting means for changing the penetration depth; and stimulation means for stimulating the area surrounding the incision and facilitating the extraction of the sample of bodily fluid.